Various types of web page authoring tools exist. Some of these tools allow users to produce web pages in a “What You See Is What You Get” (WYSIWYG) mode, i.e. the user is able to see what the final product will look like in a browser while editing the page. Many of these tools must be installed on a user's computer, and require full local access to all functions used by the web pages being edited. For example, if a user wants to use a particular function in a web page, not only the web page authoring tool but also the library explaining how to implement the function must be installed on the user's computer.
Other web page authoring tools exist that are implemented via a web browser. These tools, however, have limited functionality compared to client-based tools. This stems, in part, from the restrictions that have been placed on web browsers given concerns regarding security and the possibility of unauthorized access to a computer through the web browser. Among these restrictions is a limit on what other data and facilities on the user's computer the browser can access. Libraries of the type used by many client-based tools often are restricted from being used by browser-based tools. Thus, conventional browser-based tools cannot replicate the richness of functionality available in client-based tools.